Influence of Differential Calcification in the Descending Thoracic Aorta on Aortic Pulse Pressure

Abstract

Purpose: Multiple studies have shown pulse pressure (PP) to be a strong predictor of aortic calcification. However, no studies are available that correlate PP with aortic calcification at the segmental level. Methods: We identified 37 patients with aortic PP measured during cardiac catheterization. Their noncontrast chest computed tomography scans were evaluated for the presence of calcium in different segments (ascending aorta, arch of aorta [arch], descending aorta) and quantified. Patients with calcification (Calcified Group A) were compared against patients without calcification (Noncalcified Group B) in terms of PP, calcification and compliance. Results: The mean of the total calcium score was higher in the descending aorta than the arch or ascending aorta (691 vs 571 vs 131, respectively, P < 0.0001). PP had the strongest correlation with calcification in the descending aorta (r = 0.47, P = 0.004). Calcified Group A had a much higher PP than Noncalcified Group B, with the greatest difference in the descending aorta (20 mmHg, P < 0.0001), lesser in the ascending aorta (10 mmHg, P = 0.12) and the least in the arch (5 mmHg, P = 0.38). Calcified Group A patients also had much lower compliance than Noncalcified Group B patients, with the greatest difference among groups seen in the descending aorta (0.7 mL/mmHg, P = 0.002), followed by the ascending aorta, then arch. Conclusions: These are the first data to evaluate the relative impact of aortic segments in PP. Finding the greatest amount of calcification along with greatest change in PP and compliance in the descending aorta makes a case that the descending aorta plays a major role in PP as compared to other segments of the thoracic aorta.

Keywords

• thoracic aortic
• calcification
• pulse pressure
• compliance
• computed tomography